Originally Posted by

**ugkwan** The question simply ask to write the partial fraction decomposition of the rational expression.

(x^2) / (x^4 - 2x^2 - 8)

I wrote it out as:

(A / (x-2)) + (B / (x+2)) + ((Cx+D) / (x^2+2))

I got as far as simplifying it as:

Ax^3+2Ax^2+2Ax+4A+Bx^3-2Bx^2+2Bx-4B+Cx^3-4Cx+Dx^2-4D

So I group them up as:

(A+B+C)x^3]=0

(2A-2B+D)x^2=1

(2A+2B-4C)]x=0

(A-B-D)4=0

Now I'm lost in using the elimination method because I just don't see how to peace together this puzzle, and the use the answer to complete the partial fraction decomposition. OMG I need some assistance please, this problem is driving me mad...